Single ended = large images?

@montaldo sure, I started with KT150s in my QS M120s. They have a little more top end and a little more bottom end compared to the KT120s. I came from Cary, EL34s and Triode amps too. For me, I will always favor that EL34 midrange type of bloomy sound vs something more analytical with just more detail and more bass. Mids for me is where the music is at. Guitars and Piano keys gotta sound engaging. I was never going to be able to find enough power with 300B amps. Cary FE 211s are massive amps, high voltage room heaters. If I had a large separate room, with more AC - I might have gone that route or maybe not.  Too big really.  Mike’s smaller QS Mid Monos with EL34s are short on power and drive for my particular custom 6ohm 92.5db speakers I built. So, Mike and I talked. He felt I might like KT120s more. Started going back through friends with CJs. and the CJ forums, they like the KT120s there too. I later realized KT120 might have been closer to what I like. Af first I did not like them. Tried them twice in fact. Next I then let them settle in about 100hrs and realized it was headed in the right direction. I had played around [a lot] with the small input/driver tubes on the QS 120s, similar to how some of the V4s are set up. I have the other EVO Silver-Gold non-oiler caps. Exact same ones Cary uses on their top shelf upgrades on the FE 211s and such. The KT120s paired with vintage 1960s era Mullard 12xx7 tubes or PSVane 12xx7s up front sound nice. Particularly so when paired with the upper end Mundorf caps. When the amp transformers get warm and saturated, the 3D layered effect occurs, sounds in front, across the front, up to the sides of me. One of my former Cary amps did that too with the same caps, but the QS M120s are cleaner sounding now after these mods. The amps transform with the right caps/tubes in them. 

Thanks for that great explanation. You and I are cut from the same cloth.  I spent years with a cj MV-52 then an MV60 and totally came from EL34 listing paradigm! I value the mid-range over everything. If it's not correct I don't care about anything else. I have voiced my system around the v4s with the KT150s, and I think the rest of my system makes them a little more mid-range wonderful, but it may be due to system balance not due to the tubes. I just bought a shunyata Everest which opened up dynamics and clarity. I think it would be really interesting to try the KT-120 tubes. I will think about that! Not sure whether trying to upgrade from mundorf Supremes in my v4s is worth it?

Thanks

Stu

One amplifier I know I loved was a vac Renaissance 30/30. Push pull 300B output tubes. It doesn't have enough power for my current speakers, but I've heard about 300B SET amps. I have to wonder how amazing they must sound. I'm going to research these a bit. Maybe they are all low powered. I have thought about a vac Renaissance 70/70 or 140/140, but the cost of 300b tubes these days is pretty daunting. The 30/30 and a shindo montrachet are probably the greatest amplifiers I've ever owned, from a goosebumps musical point of view. 

@montaldo its worth checking what you have inside first. There was a batch of guys who saw my first post about 4-5 years ago and tried them in the M120s and the V4 amps. Cannot say I recommend it unless you have a lot of patience getting through the ridiculous settle-in time on the caps I have. Check yours first to be sure.

Mine are in fact the Supreme Eco SilverGold Black SESG Series Metalized Silver Gold Polypropylene Axial, SKU: Mundorf-80510, MSRP $59.88 USD each

The REASON I went to these caps in my QS amps is I wanted to confirm how much of the sound that I was hearing from my prior upgraded Cary amps was dictated by the sound of the coupling caps alone. Sure enough, caps matter a lot. 

The downside was just how freaking long it took for these particular caps to form and settle in. Good grief.   I was pre-warned by a retired local tech friend about this on the first set of Cary amps. He was spot on.  Told me to "get ready for the roller coaster ride", and yes it was nerve-wracking at times  Both Cary and QS amps took 300hrs before things stabilized and the sound and presentation stopped changing.

4 ft violin, 12 ft wide piano etc.

I’ve always thought that with most recordings with a piano in them, the piano usually sounds nearly as long as the small room I am set up in . . . but it’s been so long since I’ve been to live music (with or without piano). . . .

Not that this applies to you and your equipment, but I remember back in the early summer of ’01 when I got my present amp (Cary V12) I was set up in a bigger room and I was frequently operating within ear-bleed parameters. I remember one early afternoon when I was the only one in the house and I had the Steve Earle/I Feel Alright CD on, and I just kept tweaking it louder and louder and louder . . . I remember describing it to a friend of mine at work, I told him it was like the picture was blowing up bigger and bigger like a balloon! I thought that the speakers might explode! Anyway, I found the experience to be a lot of good clean sonic fun, and I rather enjoyed it.